Slab-shaped speaker systems are beginning to pick up steam as an alternative to soundbars. Instead of a bar of speakers to place in front of your HDTV, you place a whole, thin block of speakers under your HDTV. This makes the sound system even less obtrusive than a soundbar and offers the potential to do some interesting things with simulated surround, by placing discrete drivers at different positions both left and right and in the front and back of the slab. That brings us to the LG SoundPlate LAP340; it's a $399.99 (direct) one-piece speaker system that has some useful features and practically vanishes under an HDTV. Unfortunately, the sound it puts out just isn't that big.

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DesignThe SoundPlate is a simple, 1.4-inch-thick black slab measuring 27.6 by 12.6 inches (WD). According to LG, it can support an HDTV measuring 32 to 55 inches, and in my tests, held up a 46-inch Samsung UN46F5000AF with ease. Since you'll be counting on this to be the base for your HDTV, you need to make sure the screen's foot is centered on the speaker; it's designed to hold weight in the middle, not near the edges. A black metal grille runs along the front and sides of the SoundPlate, and the back holds a minimum of controls and connections: an optical audio input, a power port, a switch to set the auto power mode on or off, and Power, Volume, and Function buttons. The lack of any analog audio inputs is curious, and limits the SoundPlate's flexibility if your devices don't have either an optical audio output or Bluetooth.

The remote is a simple, flat black and silver rectangle with six buttons and a Volume Up/Down rocker. The buttons include Power, Cinema Sound (mode toggle), Mute, Optical input, Bluetooth, and LG TV. The LG TV button activates the wireless LG SoundSync feature, which lets you connect the SoundPlate to your LG HDTV wirelessly if it also supports SoundSync. We did not have a compatible screen available to test this feature.

PerformanceLG doesn't list the SoundPlate's individual drivers, but it dedicates 20 watts each to the four front and surround left/right channels and another 40 watts to the built-in twin subwoofers, for a total power rating of 120 watts. This is pretty anemic, as most HDTV speakers use around 5-10 watts of power and similarly priced stereo soundbars at least quadruple/octuple the power per channel, not counting any connected subwoofer.

For movies, the SoundPlate sounds underpowered when compared to other one-piece speaker systems, though it does offer a solid boost in volume and clarity over most HDTVs' built-in speakers. In The Amazing Spider-Man, when Spider-Man menaces a car thief, his dialogue and the high-pitched thwips of his web shooters sound punchy but lack much force, and the scene sounds underwhelming and small even with the Cinema Sound mode turned on. The 25th anniversary performance of The Phantom of the Opera sounded much louder, but mostly due to the extremes of the orchestra. During the entr'acte, the horns and flutes boomed satisfyingly, but the bright highs sounded grating, and the lows teetered on the edge of distortion. The room filled with sound, but that sound lacked the clarity and depth it really could have used to make the experience more immersive. The masquerade scene felt slightly flat, with the deep bass of plucked strings offering very little force. While the SoundPlate boasts twin built-in subwoofers, they don't offer the sort of power a single external subwoofer would offer, or even the bass levels presented by other subwoofer-free soundbars like the Polk N1 Surroundbar and the Vizio S5340W-C2.

The SoundPlate fares a bit disappointingly when playing music as well. Deep bass notes, like the synth bass and kick drum hits in The Knife's "Silent Shout," tend to distort at maximum volume, and even when they don't distort, the vibrations caused any minor amount of wiggle room in the HDTV above it to buzz. If your screen can pivot left or right or is slightly wobbly, expect heavy bass to make it vibrate noticeably. The SoundPlate's mids and highs sound a bit better, if too soft with Cinema Sound disabled, and easily swallowed by distortions and vibrations from bass with Cinema Sound enabled. The upright bass in Primus' "Mr. Krinkle" was suitably deep and imposing, but the texture of the individual strings disappeared in the indistinct low end, and Les Claypool's vocals faded into the background. What I could hear sounded crisp and clear, but it just wasn't strong enough against the low-end of the mix.

The LG SoundPlate LAP340 is a speaker system that sounds good on paper, but its small, concealable size comes at the cost of power. Its subtle, stealthy design and useful features like Bluetooth and (if you have a compatible LG HDTV) LG SoundSync make it attractive visually, but for a $400 home theater sound system it just doesn't put out a sound field that's loud or crisp enough. Soundbars like the Polk N1 and Vizio S5340W offer much more bang for your buck, and the Editors' Choice Sony HT-CT260 adds a wireless subwoofer to the mix for superior bass performance.

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Will Greenwald has been covering consumer technology for more than six years, and has served on the editorial staffs of CNET.com, Sound & Vision, and Maximum PC. Since graduating from Syracuse University in 2005, Will has been an active technology journalist both online and in print. His work and analysis has been seen in GamePro, Tested.com, Geek.com, and several other publications. He currently covers consumer electronics in the PCMag.com labs, focusing on Blu-ray players, set-top boxes, and other home theater equipment.
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